Bounding Box Intersection over Union (BBox IoU).
In [1]}, the authors added a new branch on top of the Fast R-CNN model to estimate standard deviation of each bounding box and use it at Non-maximum Suppression (NMS) level to give more weight to the less uncertain ones.
In [2]}, [3]}, the authors added a new branch on top of the Faster R-CNN to regress bounding box IoU and to multiply this value with the classification score to compute final score of the suppression criterion of the NMS.
In the same direction, Fitness NMS was proposed in [4]} to correct the detection score for better selecting bounding boxes which maximize their estimated IoU with the ground-truth.
